1
2// (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, Howard
3// Hinnant & John Maddock 2000.
4// Use, modification and distribution are subject to the Boost Software License,
5// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
6// http://www.boost.org/LICENSE_1_0.txt).
7//
8// See http://www.boost.org/libs/type_traits for most recent version including documentation.
9
10#ifndef BOOST_TT_ADD_CONST_HPP_INCLUDED
11#define BOOST_TT_ADD_CONST_HPP_INCLUDED
12
13#include <boost/type_traits/detail/config.hpp>
14
15namespace boost {
16
17// * convert a type T to const type - add_const<T>
18// this is not required since the result is always
19// the same as "T const", but it does suppress warnings
20// from some compilers:
21
22#if defined(BOOST_MSVC)
23// This bogus warning will appear when add_const is applied to a
24// const volatile reference because we can't detect const volatile
25// references with MSVC6.
26# pragma warning(push)
27# pragma warning(disable:4181) // warning C4181: qualifier applied to reference type ignored
28#endif
29
30 template <class T> struct add_const
31 {
32 typedef T const type;
33 };
34
35#if defined(BOOST_MSVC)
36# pragma warning(pop)
37#endif
38
39 template <class T> struct add_const<T&>
40 {
41 typedef T& type;
42 };
43
44#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
45
46 template <class T> using add_const_t = typename add_const<T>::type;
47
48#endif
49
50} // namespace boost
51
52#endif // BOOST_TT_ADD_CONST_HPP_INCLUDED
53